The use of such expanded-metal grids in the plates of electrical batteries, especially those of the lead-acid type, is already well known. Reference in this connection may be made, for example, to U.S. Pat. Nos. 3,853,626, 3,945,097 and 4,102,024. Thus, as described in these prior patents, the grid is produced by slitting a sheet of lead or other metal to form a multiplicity of tiers of longitudinally separated cuts, with relative staggering by half a pitch in adjacent tiers, and then stretching the sheet to expand these cuts into generally rhomboidal meshes or cells. The meshes are bounded by webs of the metal interconnected by nodes of twice the web width, the webs and the nodes experiencing a twisting action during the stretching operation whereby the nodes are turned through almost 90.degree. from their original positions. With the use of thin sheets (thickness up to about 0.05 inch or 1.25 mm as suggested in the two first-mentioned patents), and with webs having a width of the same order of magnitude, the height of the twisted nodes substantially exceeds the thickness of the sheet whereby these nodes project beyond the levels of the faces of a pair of solid border strips formed by unslitted sheet portions on opposite edges of the rectangular grid area; the usual ratio of sheet thickness to web width lies between 1:1.2 and 1:1.3. Since the projecting nodes would constitute discontinuities in the surface of the pasted-up plate, it becomes necessary to subject the grid to a separate flattening operation which, however is resisted by the solid reinforcing strips; the latter, accordingly, must undergo a certain lengthening process. The equipment needed for these supplemental operation is cumbersome and expensive.
The preference of the art for thin metal sheets is partly due to the realization that battery grids die-cut from such a sheet, formed with integral terminal tabs which project beyond their generally rectangular outlines, unavoidably leave a certain residue in the form of scrap metal which becomes more significant as the sheet thickness increases. With heavier sheets the width of the tabs can be reduced for a given cross-sectional area, as determined by the maximum permissible electrical resistance, yet this only increases the amount of metal going to waste.